Generally, in semiconductor manufacturing processes, wafers are produced, and the produced wafers are transferred to the following stage so as to manufacture a semiconductor package.
In this case, the produced wafers are not immediately used for the following stage, but are sent to the following stage in order if necessary after being stocked for a given period of time. Thus, a facility for such stocking is required.
The facility for the stocking is installed on the ground in a semiconductor factory, and there is a problem that a large space is occupied.
Additionally, during the stocking in the stocking facility the wafers may be damaged as time goes by. In order to prevent this damage, during the stocking in the stocking facility or when gas is injected before the stocking, gas may leak from a container in which the wafers are contained, and the concentration of the gas in the air may become high.